Composition effect on the phase morphology in polyethylene (PE) with polyamide (PA) blends was investigated by pattern analysis of scanning electron micrographs. The average diameter denoted as d(g) is defined to discuss the morphology of the blends and further, different fractal dimensions, D-M and D-N, were introduced to characterize the phase morphology. Scale function S-N(r) and S-M(r) are defined to study the selfsimilarity of the phase morphology. The plots of S-N(r)/S-N(r)m (the maximum of S-N(r)) versus r/rm (the maximum of r) and S-M(r)/S-M(r)m (the maximum of Sm(r)) versus r/rm showed the selfsimilar formation of the phase pattern. Furthermore, we calculated the fractal dimension D of different PE/PA blends. The results showed that the fractal dimension was an effective parameter to describe the spacial distribution of dispersed particles. (C) 2008 Wiley Periodicals, Inc.